JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
Let \(\alpha \in(0, \infty)\) and \(A=\left[\begin{array}{lll}1 & 2 & \alpha \\ 1 & 0 & 1 \\ 0 & 1 & 2\end{array}\right]\). If \(\operatorname{det}\left(\operatorname{adj}\left(2 \mathrm{~A}-\mathrm{A}^{\mathrm{T}}\right) \cdot \operatorname{adj}\left(\mathrm{A}-2 \mathrm{~A}^{\mathrm{T}}\right)\right)=2^8\), then \((\operatorname{det}(\mathrm{A}))^2\) is equal to :
- A \(1\)
- B \(49\)
- C \(16\)
- D \(36\)
Answer & Solution
Correct Answer
(C) \(16\)
Step-by-step Solution
Detailed explanation
\( \left|\operatorname{adj}\left(\mathrm{A}-2 \mathrm{~A}^{\mathrm{T}}\right)\left(2 \mathrm{~A}-\mathrm{A}^{\mathrm{T}}\right)\right|=28 \) \( \left|\left(\mathrm{~A}-2 \mathrm{~A}^{\mathrm{T}}\right)\left(2 \mathrm{~A}-\mathrm{A}^{\mathrm{T}}\right)\right|=24 \)…
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